mm: remove __GFP_NO_KSWAPD

When transparent huge pages were introduced, memory compaction and swap
storms were an issue, and the kernel had to be careful to not make THP
allocations cause pageout or compaction.

Now that we have working compaction deferral, kswapd is smart enough to
invoke compaction and the quadratic behaviour around isolate_free_pages
has been fixed, it should be safe to remove __GFP_NO_KSWAPD.

[minchan@kernel.org: Comment fix]
[mgorman@suse.de: Avoid direct reclaim for deferred compaction]
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c13ea7538891..5e92698e5395 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2362,9 +2362,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
                 goto nopage;
 
 restart:
-        if (!(gfp_mask & __GFP_NO_KSWAPD))
-                wake_all_kswapd(order, zonelist, high_zoneidx,
-                                                zone_idx(preferred_zone));
+        wake_all_kswapd(order, zonelist, high_zoneidx,
+                                        zone_idx(preferred_zone));
 
         /*
          * OK, we're below the kswapd watermark and have kicked background
@@ -2441,7 +2440,7 @@ rebalance:
          * system then fail the allocation instead of entering direct reclaim.
          */
         if ((deferred_compaction || contended_compaction) &&
-                                                (gfp_mask & __GFP_NO_KSWAPD))
+            (gfp_mask & (__GFP_MOVABLE|__GFP_REPEAT)) == __GFP_MOVABLE)
                 goto nopage;
 
         /* Try direct reclaim and then allocating */